1. Field of the Invention
The present invention relates to a receiving circuit for optical communication, and, more particularly, is suitably applied to a receiving circuit for optical communication used in complementary optical transmission.
2. Description of the Related Art
In optical communication, photoelectric conversion is performed by using a light receiving element. When the pulse width of signal light is long, current consumption increases because an electric current flows to the light receiving element for a long time. Therefore, there is a method of using a complementary optical wiring circuit to prevent the electric current from flowing to the light receiving element for a long time. The complementary optical wiring circuit transmits only a rising edge (set pulse light) and a falling edge (reset pulse light) of the signal light and restores an original signal from the rising edge and the falling edge.
For example, Japanese Patent Application Laid-Open No. 2001-285195 discloses a method for suppressing output drift of a complementary optical wiring circuit. The complementary optical wiring circuit includes first and second diode-type light emitting elements serially connected to each other, a coupling capacitor connected to a connection point of the first and second diode-type light emitting elements, a pulse signal source for alternately applying a differential waveform signal to the first and second diode-type light emitting elements via the coupling capacitor, and a DC bias voltage source connected between an anode of the first diode-type light emitting element and a cathode of the second diode-type light emitting element.
However, the receiving circuit for optical communication in the past performs photoelectric conversion for the set pulse light and photoelectric conversion for the reset pulse light independently from each other. Therefore, when noise rides on the set pulse light or the reset pulse light during the transmission of the set pulse light and the reset pulse light, the noise cannot be eliminated.